Security Update - ISTIO-SECURITY-003 and ISTIO-SECURITY-004

By The Istio Team |  August 13, 2019 |  3 minute read

Today we are releasing two new versions of Istio. Istio 1.1.13 and 1.2.4 address vulnerabilities that can be used to mount a Denial of Service (DoS) attack against services using Istio.

ISTIO-SECURITY-2019-003: An Envoy user reported publicly an issue (c.f. Envoy Issue 7728) about regular expressions (or regex) matching that crashes Envoy with very large URIs.

  • CVE-2019-14993: After investigation, the Istio team has found that this issue could be leveraged for a DoS attack in Istio, if users are employing regular expressions in some of the Istio APIs: JWT, VirtualService, HTTPAPISpecBinding, QuotaSpecBinding.

ISTIO-SECURITY-2019-004: Envoy, and subsequently Istio are vulnerable to a series of trivial HTTP/2-based DoS attacks:

  • CVE-2019-9512: HTTP/2 flood using PING frames and queuing of response PING ACK frames that results in unbounded memory growth (which can lead to out of memory conditions).
  • CVE-2019-9513: HTTP/2 flood using PRIORITY frames that results in excessive CPU usage and starvation of other clients.
  • CVE-2019-9514: HTTP/2 flood using HEADERS frames with invalid HTTP headers and queuing of response RST_STREAM frames that results in unbounded memory growth (which can lead to out of memory conditions).
  • CVE-2019-9515: HTTP/2 flood using SETTINGS frames and queuing of SETTINGS ACK frames that results in unbounded memory growth (which can lead to out of memory conditions).
  • CVE-2019-9518: HTTP/2 flood using frames with an empty payload that results in excessive CPU usage and starvation of other clients.
  • See this security bulletin for more information

Those HTTP/2-based vulnerabilities were reported externally and affect multiple proxy implementations.

Affected Istio releases

The following Istio releases are vulnerable:

  • 1.1, 1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.1.5, 1.1.6, 1.1.7, 1.1.8, 1.1.9, 1.1.10, 1.1.11, 1.1.12
  • 1.2, 1.2.1, 1.2.2, 1.2.3

All versions prior to 1.1 are no longer supported and are considered vulnerable.

Impact score

Vulnerability impact and detection

ISTIO-SECURITY-2019-003: To detect if there is any regular expressions used in Istio APIs in your cluster, run the following command which prints either of the following output:

  • YOU ARE AFFECTED: found regex used in AuthenticationPolicy or VirtualService
  • YOU ARE NOT AFFECTED: did not find regex usage
$ cat <<'EOF' | bash -
set -e
set -u
set -o pipefail

red=`tput setaf 1`
green=`tput setaf 2`
reset=`tput sgr0`

echo "Checking regex usage in Istio API ..."

AFFECTED=()

JWT_REGEX=()
JWT_REGEX+=($(kubectl get Policy --all-namespaces -o jsonpath='{..regex}'))
JWT_REGEX+=($(kubectl get MeshPolicy --all-namespaces -o jsonpath='{..regex}'))
if [ "${#JWT_REGEX[@]}" != 0 ]; then
  AFFECTED+=("AuthenticationPolicy")
fi

VS_REGEX=()
VS_REGEX+=($(kubectl get VirtualService --all-namespaces -o jsonpath='{..regex}'))
if [ "${#VS_REGEX[@]}" != 0 ]; then
  AFFECTED+=("VirtualService")
fi

HTTPAPI_REGEX=()
HTTPAPI_REGEX+=($(kubectl get HTTPAPISpec --all-namespaces -o jsonpath='{..regex}'))
if [ "${#HTTPAPI_REGEX[@]}" != 0 ]; then
  AFFECTED+=("HTTPAPISpec")
fi

QUOTA_REGEX=()
QUOTA_REGEX+=($(kubectl get QuotaSpec --all-namespaces -o jsonpath='{..regex}'))
if [ "${#QUOTA_REGEX[@]}" != 0 ]; then
  AFFECTED+=("QuotaSpec")
fi

if [ "${#AFFECTED[@]}" != 0 ]; then
  echo "${red}YOU ARE AFFECTED: found regex used in ${AFFECTED[@]}${reset}"
  exit 1
fi

echo "${green}YOU ARE NOT AFFECTED: did not find regex usage${reset}"
EOF

ISTIO-SECURITY-2019-004: If Istio terminates externally originated HTTP then it is vulnerable. If Istio is instead fronted by an intermediary that terminates HTTP (e.g., a HTTP load balancer), then that intermediary would protect Istio, assuming the intermediary is not itself vulnerable to the same HTTP/2 exploits.

Mitigations

For both vulnerabilities:

  • For Istio 1.1.x deployments: update to a minimum version of Istio 1.1.13
  • For Istio 1.2.x deployments: update to a minimum version of Istio 1.2.4

We’d like to remind our community to follow the vulnerability reporting process to report any bug that can result in a security vulnerability.